Sound Deadening 101
Le Mans Master
Joined: Aug 2005
Posts: 7,201
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From: DP(oh you know where) IL
St. Jude Donor '06
oh yea. we hang out and have a good time. We have found that we usually cause the thread to go away from the original topic very quickly
Team Owner
Joined: Sep 2006
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From: Beats UD regularly playing 3D chess, and at life
Intermediate
Joined: Jan 2007
Posts: 44
Likes: 0
From: Taylor Michigan
Actually, fiber absorbs sound better than foam. I haven't taken my floor out of my 94, but if I do and it's got fiber on the back, I will be stuffing more fiber in the nooks and crannys and behind trim panels to absorb the road noise. Foam is mostly a space filler to decouple the carpet from the sheet metal. It absorbs a little, but not like fiber!
And the damper stuff works great to minimize the vibrations. Damping the flatest panels will give you the best bang for the buck. Butyl is best for most people unless you can bake the car to adhere the asphalt stuff..
Former Vendor
Joined: Nov 2005
Posts: 8,995
Likes: 2
From: Spring Texas
St. Jude Donor '08
After reasding a little more into sound insulation, glass fiber material is the best for sound deadening. It's commonly used in recording studios. Foam is good but it's designed for automotive use because of it's small size compared to the glass fiber.
Le Mans Master
Joined: Aug 2005
Posts: 7,201
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From: DP(oh you know where) IL
St. Jude Donor '06
important in cars
Last edited by DPG; Mar 1, 2007 at 03:50 PM.
Thread Starter
Team Owner
Joined: Feb 2000
Posts: 51,504
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From: Sacramento CA
You really don't want glass fibers floating around in your car.
Intermediate
Joined: Jan 2007
Posts: 44
Likes: 0
From: Taylor Michigan
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Racer
Joined: Feb 2006
Posts: 251
Likes: 1
From: Katonah NY
Just remember that fiberglass is basically useless if it gets wet, which is another reason closed cell foam is usually better. But then again, foam can't take much heat while fiberglass can...
Race Director
Joined: Sep 2004
Posts: 17,786
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From: Redsox, Pats, Celts & Bruins !!! Redsox Nation !!!
St. Jude Donor '06-'07-'08-'09-'10-'11-'12
My favorite quote from that site
If you really need to do this in the absolutely least expensive way and are not convinced or concerned by the demonstrated inferiority of asphalt based sound deadeners, go to Home Depot or Lowes and get a roll or two of Peel & Seal. This is the least expensive option and you won't have to worry about shipping costs. I can see no difference in Peel & Seal and the asphalt based aluminum skinned products in this review. If you are going to live dangerously, do it right.
Former Vendor
Joined: Nov 2005
Posts: 8,995
Likes: 2
From: Spring Texas
St. Jude Donor '08
Took my vette on the first road test since the system install on sunday. DRASTIC improvement. My main concern was resonance from my borla stingers. I used 2 bulk kits of Dynamat Extreme, a Door kit of second skin damplifier pro, and 3 sheets of second skin overkill pro. The Car is so Silent on the inside. The noise reduction is incredible. if you're planning on running a system, i HIGHLY reccomend sound deadening/absorbing material.
here are some pics.
main area:
Overkill pro (behind the EQ brain)
door:
here are some pics.
main area:
Overkill pro (behind the EQ brain)
door:
Racer
Joined: Mar 2007
Posts: 278
Likes: 2
From: Wellington Florida
Wow! I just found this board a few hours ago. Really something. As it turns out I have a 69 roadster with 427. I just finished doing the entire interior with dynamat extreme. Very big job. I was unaware of all of these other deadening products until this thread. I originally did it to deaden the road and exhaust noise. It certainly helped, but the exhaust is still to loud at highway speeds. What do you guys recommend to cut the exhaust noise in the interior. Also, has anyone heard of a product call Koolmat? I had purchased this too, and installed it on top of the dynamat on the floor and tunnel. Its claim to fame is heat reduction and sound deadening. It is fiberglass matt embedded in a silicone backing.
Le Mans Master
Joined: Aug 2005
Posts: 7,201
Likes: 0
From: DP(oh you know where) IL
St. Jude Donor '06
Wow! I just found this board a few hours ago. Really something. As it turns out I have a 69 roadster with 427. I just finished doing the entire interior with dynamat extreme. Very big job. I was unaware of all of these other deadening products until this thread. I originally did it to deaden the road and exhaust noise. It certainly helped, but the exhaust is still to loud at highway speeds. What do you guys recommend to cut the exhaust noise in the interior. Also, has anyone heard of a product call Koolmat? I had purchased this too, and installed it on top of the dynamat on the floor and tunnel. Its claim to fame is heat reduction and sound deadening. It is fiberglass matt embedded in a silicone backing.
Former Vendor
Joined: Nov 2005
Posts: 8,995
Likes: 2
From: Spring Texas
St. Jude Donor '08
Wow! I just found this board a few hours ago. Really something. As it turns out I have a 69 roadster with 427. I just finished doing the entire interior with dynamat extreme. Very big job. I was unaware of all of these other deadening products until this thread. I originally did it to deaden the road and exhaust noise. It certainly helped, but the exhaust is still to loud at highway speeds. What do you guys recommend to cut the exhaust noise in the interior. Also, has anyone heard of a product call Koolmat? I had purchased this too, and installed it on top of the dynamat on the floor and tunnel. Its claim to fame is heat reduction and sound deadening. It is fiberglass matt embedded in a silicone backing.
reducing exhaust noise is somthing very easy....as long as you can pinpoint where most of the noise is coming from. (usually the mufflers) I'm not familier with your setup, but if you have side pipes or somthing radical. it's going to be more difficult.
I'd reccomend closed cell foam (like second skin's "overkill pro" or Vcomp foam by B-quiet) to absorb the sound waves from your exhaust.
the best way to tackle this by realizing that sound waves behave like light from an open light bulb. they radiate in all directions and reflect off certain surfaces.
For sound waves, they reflect off hard smooth surfaces. and when the wave hits a surface that is perpendicular to it's motion, it passes through the surface with the least amount of resistance. this is why the area behind the seats on a C5 is so detremental because of the lack of padding and the large flat surface being at an angle perpendicular to the mufflers' sound waves.
One layer of SS overkill pro provided significant reduction in noise (especially the dreaded 2K RPM drone) from my borlas. Closed cell foamworks based on density and thickness. A thicker or denser foam will block increasingly lower frequencies. if you do it just right, you get an exhaust setup that you can't hear, but feel.
Le Mans Master
Joined: Aug 2005
Posts: 7,201
Likes: 0
From: DP(oh you know where) IL
St. Jude Donor '06
First:
reducing exhaust noise is somthing very easy....as long as you can pinpoint where most of the noise is coming from. (usually the mufflers) I'm not familier with your setup, but if you have side pipes or somthing radical. it's going to be more difficult.
I'd reccomend closed cell foam (like second skin's "overkill pro" or Vcomp foam by B-quiet) to absorb the sound waves from your exhaust.
the best way to tackle this by realizing that sound waves behave like light from an open light bulb. they radiate in all directions and reflect off certain surfaces.
For sound waves, they reflect off hard smooth surfaces. and when the wave hits a surface that is perpendicular to it's motion, it passes through the surface with the least amount of resistance. this is why the area behind the seats on a C5 is so detremental because of the lack of padding and the large flat surface being at an angle perpendicular to the mufflers' sound waves.
One layer of SS overkill pro provided significant reduction in noise (especially the dreaded 2K RPM drone) from my borlas. Closed cell foamworks based on density and thickness. A thicker or denser foam will block increasingly lower frequencies. if you do it just right, you get an exhaust setup that you can't hear, but feel.
reducing exhaust noise is somthing very easy....as long as you can pinpoint where most of the noise is coming from. (usually the mufflers) I'm not familier with your setup, but if you have side pipes or somthing radical. it's going to be more difficult.
I'd reccomend closed cell foam (like second skin's "overkill pro" or Vcomp foam by B-quiet) to absorb the sound waves from your exhaust.
the best way to tackle this by realizing that sound waves behave like light from an open light bulb. they radiate in all directions and reflect off certain surfaces.
For sound waves, they reflect off hard smooth surfaces. and when the wave hits a surface that is perpendicular to it's motion, it passes through the surface with the least amount of resistance. this is why the area behind the seats on a C5 is so detremental because of the lack of padding and the large flat surface being at an angle perpendicular to the mufflers' sound waves.
One layer of SS overkill pro provided significant reduction in noise (especially the dreaded 2K RPM drone) from my borlas. Closed cell foamworks based on density and thickness. A thicker or denser foam will block increasingly lower frequencies. if you do it just right, you get an exhaust setup that you can't hear, but feel.
good advice here
Racer
Joined: Mar 2007
Posts: 278
Likes: 2
From: Wellington Florida
Jesus, Radio Flyer it is quite clear you have forgotten more about sound deadening, etc. than I am ever going to know. Great info. Let me elaborate on my setup a little more to make sure I understand your recommendations. The rear area of a c3 is much like the picture of your c5 except the bottom is flat. There is a vertical wall at the very back though, like yours. I have dynamatted this area entirely already, but if I understand you correctly, you would advocate putting these other products on the these areas, right? The mufller setup I have exits at the rear of the car. It is 3" with flowmaster delta flows. The mufflers are tilted at about a 45 degree angle under the very back of the car and tucked up underneath. The gas tank is right above them and behind them and the compartment we are talking about is behind the gas tank.
Keep in mind I am not familiar with the products you are talking about. Do they spray on, are they self adhesive sheet type. Please elaborate. Also is there something I should spray above and around the fiberglass shell over the mufflers. Thanks again.
Keep in mind I am not familiar with the products you are talking about. Do they spray on, are they self adhesive sheet type. Please elaborate. Also is there something I should spray above and around the fiberglass shell over the mufflers. Thanks again.
Racer
Joined: Mar 2007
Posts: 278
Likes: 2
From: Wellington Florida
DPG, I am not sure this was clear in my first reply, but I already put in the Koolmat. Problem is that it is a precut kit for the front floor and tunnel. It doesn't cover any of the rear area. Seems like a good product and not real heavy. It is extremely heat resistant. The fiberglass side will hand 1100 degrees and the silicone side 500 degrees. They have a web site if you are interested. One drawback is it is not self adhesive. You have to cut it to fit and then glue it down with silicone or spray adhesive. They claim up to a 23db sound reduction with it though.
Le Mans Master
Joined: Aug 2005
Posts: 7,201
Likes: 0
From: DP(oh you know where) IL
St. Jude Donor '06
Irish. When I had my c3, i remember that the rear cargo area was great for magnifying exhaust noise because of the lack of insulation and the shape of the area as well helped direct that noise to you up front!
If the kool mat stuff isn't really expensive, I would go with that. What Radio Flyer is talking about is this foam type insulation that is used for road noise and exhaust noise. I will try to find a thread so you can see what it looks like.
If the kool mat stuff isn't really expensive, I would go with that. What Radio Flyer is talking about is this foam type insulation that is used for road noise and exhaust noise. I will try to find a thread so you can see what it looks like.